John l



J. L. WHEELER.

SEWING MACHINE.

APPLICATION FILED NOV.23.'l917.

l ,427, 1 40, Patented Aug. 29, 1922.

' nrsmao.

tlhll fiilil JOHN L. VTI-IEELER, 0. 3 ST. LOUIS, MISSOURI, A$SIGNOR TO SIMPLEX SHOE M rarest c rricsi COMPANY, OF ST. LOUIS, MISSO'IJ'BI, A CGRPORATION OF MISSOURI.

SEWING MCACHINE.

To all whom it may concern:

Be it knownthat 1, JOHN L. VVHEELER, a citizen of the United States, residing in the city of St. Louis and State of Missouri, have invented new and useful Improvements in Sewing Machines, of which the following is a specification. i

This invention relates to sewing ma chines, and, without being limited thereto, has more particularly to do with machines for sewing leather and similar heavy material. It relates particularly to the threadmeasuring and take-up mechanism and has for its principal object to secure and maiindifiicult and troublesome to attain with exact,

nicety, often taking up considerable time, even by an expert operator; and after proper adjustment is effected the tension device frequently works loose or tightens or is changed by the operator or someone meddling with the machine. This has been found to be the cause of imperfect stitching or the breaking of the thread in many instances, which disadvantage is overcome by the present invention. I I

The invention consists primarily in the utilization of a weight-applied tension device of novel construction and arrangement, and, further, in the parts and combinations and arrangements of parts hereinafter described and claimed.

In the accompanying drawing illustrating a practical embodiment of the ,invention,--

Figure l is a side elevation of a sewing machine showing the thread-measuring and take-up mechanism and so much of the stitch-forming mechanism necessary to a full understanding of the operation thereof;

Figure 2 is a top plan view of the tension device detached; t

Figure 3 is a section on the line 33 of Figure 2;

Figure his a face view of the thread- I Specification of Letters Patent. Pgttngnted Quo- J l 5. Application filed November 23, 1917. Serial No. 203,516.

eral l indicatesthe standard or wheel of the tens i i Stud the f b on lClGVlCB, the supporting re or eing SlOWll 1n cross section; and Figure 5 1s a similar view of one of the clamping disks.

1' ltererring now to the drawing, the numsupporting column for the machine at the top ofwhich s a bed-plate or table 2. On the bed platc s the machine-head 3 at the front of which is a work-support l. 7 (lo-operating with the worlnsupport 1s a Presser-foot 5 and worlnng through the work-support, in proximity to the presser-foot, is an arcuate needle 6 which 18 guided in its movement by a fixed gu1de-member7 and 'a movable gu1de-member S mounted onthe head 3.

All of these parts are embodied in the invention disclosed in Letters Patent granted to hlyers and Wheeler, No. 1,188,474. and dated June 27, 1916. Hence, no further detailed description thereof will be herein given other than to state that the needle ACHINERY carries a loop of the stitching thread through the work upon each reciprocation p thereor and the loop is interlocked with a loop ora locking thread on the underside of thework.

The stitching thread, indicated by the numeral 9, is taken from a source of supply (not shown),through the tension device to be presently described, and thence about the thread-measuriug, take-up and stitch-setting mechanism substantially as set forth .in said Letters Patent aforesaid. vThis mechanism will now be described sufliciently to an understanding of the operation thereof as far as it concerns the present invention. a On the top of the head3 is a threadclamping device 10 which is in the form a hinged plate} Co-operating therewith is a lever 11 which is pivoted on the head 3, as

at 12. At the upper end of this lever is an adjusting screw which is arranged to bear, against the device 10. The other end of 11 is a stitch-setting lever 18 at whose upper end is a pulley 19, while at the opposite end thereof is a roller which works in a camgroove 21 formed in the face of the disk 16. Pivoted on the bed-plate 2, as at 22, is a threac'l-nae'asuring lever 23 having a roller 2% which works in a cam-groove 25 formed in the face of the disk 16 opposite to that in which the groove 21 occurs. Pivoted, as at 26, near the upper end of the lever 23, is a supplemental arm 27 having a pulley 28 at its outer end on opposite sides of which are thread-guides 29. This arm 2'? is limited in its'mov'ement by studs 30 on the lever 23, and it is yie'ldably held in the position shown in the drawing by a spring-pressed pin 31 workingin a tubular extension of the lever 23.

Secured to the head 3, as at 32, and havingan arm 33 secured to the hearing bracket for the power shaft 17, is a sector-bar 35 onwhich is an adjustable member 36 having a pulley 37 thereon, said member 36 being secured in position by a set-'screi'i 38. At the end of the sector-bar 35 is a pulley 39. Both of these pulleys 37, 39, have thread-guides 40 arranged on opposite sides thereof in a manner similar to the guides 29 which co operate with the pulley 23 on the supple mental arm of the lever 23.

The operation of the mechanism will now be described. The stitching thread 9 is carried through the tension device and from there is taken around the pulley 39, thence about the pulley 37, pulley 28, under the clamping device 10, over a pulley 41 at the upper front corner of the head 3, through a waking device 42, over the pulley 19, and over a pulley 4:3 to the eye of the needle 6 which takes it through the work indicated by the numeral 4 1.

The several cams on the disk 16 are so arranged and timed that during the time the needle is entering and receding from the work, the stitch-setting lever 18 is in a position with its end, on which is the pulley 19. lowered so that the thread is slack. After the needle has left the work and is continuing its upward travel the lever 23 is actuated, moving rearward rapidly. This combined movement of the needle and the lever 23 pulls the thread until the stitch is just ready for setting, the spring-pressed pin 31 permitting the supplemental arm 27 to yield so as not to draw the stitch too tight, or in other words so as not to draw the inter-looped stitching and locking threads into the puncture in the work. At this stage, the clamping, device 10 is pressed by the l'ever 11, thereby locking the thread. The thread being thus clamped, the continued rearward movement of the lever 23 pulls sufficient thread through the tension device; and at the same time the stitch-setting lever 18 is actuated to pull the interloop'ed portions of stitching and locking threads into the punctu "e in the work, or in other words, to set the stitch. Just before the needle starts again on its downward stroke, the thread-clamping device 10 is released and the lever 23 moves to its forward position so as to slacken the thread between the clamping device and the pulley 37.

Now, it is essential that the tension device through which the thread is taken from the source of supply be set and maintained eonstantiy with a predetermined or given resistance to assure the perfect workin of the thread-measuring and take-up niecanisni. As before pointed out, spring-pressed tension devices have pr'oven unreliable owing to the possibility of adjustment and accidental change. Hence, the present invention contemplates the production of a device which may be properly proportioned anc at the factory and is non-adjustable, so that there is little liability of it being accidentally or intentionally changed after the original installation.

' As shown in the drawing, the device comprises an angular block 15 having a base portion 4:6 and an upstanding portion 47.

From the upstanding portion extends a stud 418 which is flattened on one side, as at 4:9. On this stud is rotatably mounted a peripherally grooved threadqvheel on opposite sides of which are two clamping disks 51, the central opening of said disks being; fiattened correspondingly' to the flattened portion -19 of the stud so as to be non-rotatable thereon. Between the clamping disks and the threadwheel, felt or fibre washers 52 are interposed. A collar 53 is sleeved loosely on the stud between the portion -17 of the block 4.5 and tlieinner clamping disk, while a second collar 54: is likewise mounted on the stud next to the outer clamping disk.

The angular block 15 is slotted,- as at 55, 56, and has pivoted therein, as at 57, a bellcrank, one of whose arms 58 extends upward and is bifurcated, as at 59, so as to straddle the end portion of the stud and bear against the outer face of the collar 5st. The other arm 60 of the bell-crank extends substantially horizontal and has a weight 61 suspended from its outer end, preferably as shown. That is, by perforating the arm and providing the weight with a hook or loop for engagement therewith. In this ay the perforation may be located at the proper distance from the fulcrum point of the bell-crank and the weight proportioned to give the desired pressure on the tension wheel, thereby maintaining a constant given tension on the thread. If it is necessary to release the tension at any time the operator has only to raise the arm 60 of the bellcrank; and as soon as the arm is let go, the weight is again effective to restore the tension. The thread-wheel and its associated elements which are mounted loosely on the stud 48 also gives a certain amount of flexibility to the device. That is, the threadwheel is permitted to wobble somewhat without disturbing the tension to any appreciable degree when undue lateral force is exerted near the periphery of the wheel.

The tension device may be mounted on the machine at any desirable or convenient place and in any desirable manner. As shown, the block 45 is secured on a bracket extension 62 of a plate 63, and the plate is secured to the end portion of the bed-plate 2 of the machine by bolts or screws 64;, said plate having a lug 65 at its end arranged and adapted to project under the edge of the bed-plate 2 to relieve the strain on the bolts 'or screws 64 when the weight 61 is applied.

Obviously, the tension device admits of considerable modification without departing from the spirit and scope of the invention as defined in the appended claims. The invention, therefore, is not limited to the construction and arrangement shown in the accompanying drawing.

lVhat is claimed is:

1. In a sewing machine, stitch-forming mechanism, a thread-measuring and take-up mechanism operating in conjunction with said stitch-forming-mechanism, a tension de vice through which the thread passes between the source of thread supply and said thread-measuring mechanism, and a pressure device for said tension device including a lever having a weight in a predetermined fixed position thereon.

2. In a sewing machine tension, a threadwheel, and means forexerting a constant, uniform, resisting pressure on said wheel,

arm having a weight thereon in predetermined non-adjustable relation to the pivotal axis of the lever.

4. In asewing machine tension, a supporting member, a stud thereon, a threadwheel mounted loosely on said stud so as to rotate and wobble, clamping disks mounted on said stud, on opposite sides of said thread-wheel, said disks being non-rotatable but capable of endwise movement and wobbling, bearing collars mounted loosely on said stud, one of said collars being interposed between the inner clamping disk and said supporting member and the other collar being next to the outer clamping disk, the disk-engaging end portions of said bearing collars being tapered, and a lever mounted on said supporting member, one arm of said lever bearing against the outer collar and the other arm having a weight in predetermined, non-adjustable position thereon.

In testimony whereof, I have hereunto set my hand.

. JOHN L. WHEELER. 

